Resto cells and MSCs pretreated with TNF/LT support the survival of primary FL B cells. CD19⁺ B cells purified from 6 patients with FL were cultured in RPMI1640/10% FCS for 5 days, alone or with confluent Resto cells (A), cloned T-MSCs (B), or BM-MSCs (C) pretreated or not with TNF/LT for 7 days. Tumor B-cell viability was determined using CD45 and TOPRO-3 staining. Data are expressed as the absolute number of viable tumor cells (CD45⁺TOPRO-3⁻) quantified using calibrated microbeads. *Represents a significant difference in the number of viable FL cells between the compared groups (P<.05).